No, it’s not possible to install the genuine Google services on /e/OS, because /e/OS currently has microG integrated in a non-removable way, which tries its best to mimic those Google services.
And /e/OS includes further degoogling changes, which possibly could interfere with operating the genuine Google services reliably anyway.
That being said, with the help of the integrated microG your banking App might even work on /e/OS, at least for a while, but there are no guarantees … [LIST] Banking Apps on /e/OS
If you really, really need your banking App (or any Google-dependent App for that matter), in Custom ROM territory you would be better off using LineageOS in connection with the genuine Google services (installed e.g. via Open GApps) and Google’s registration of devices running uncertified Android OSes for the legitimate use of Google services at https://www.google.com/android/uncertified.